[ubuntu] Ubuntu start up error

Hi,
Do you get a Grub menu at boot time or does your machine go straight to the error?

This is one way to fix it, there probably are others.

Boot your machine and immediately start tapping the Esc key or the left Shift key to force the Grub menu to show.
In the Grub menu choose the second line (advanced options) hit Enter, then in the new screen pick the first line that has recovery in it.

After a few moments a Window pops up, here choose FSCK hit enter.
Let this finish, at the bottom of the window will be a prompt, follow those directions.

When all is done and you are back to the main window select Drop to Root Prompt, type in reboot and then hit Enter.

Now you should be back to your normal system.